Are you getting any Google capchas? DeathbyCapcha is a capcha solving service that can be used.

I often reset my IP address (turn the router off and back on again)

I'm experiencing the same. I tried different ISPs, vpn, reset router. I can fetch once some topics on some keywords, but then it returns nothing. If have to wait a bit before it allows me again. I don't have any Captcha pop ups. Not sure what's wrong. I don't have a Death ByCaptcha. It used to work. Nothing changed in my setup

Try turning down the "page fetching rate" in the settings and see whether that helps. If not, contact help desk. https://askjonleger.desk.com/ You also need to consider that not all topics have lots of material available on the internet, so the subject can have an effect.